Bernie Sanders has earned two cheers for the presidential campaign he has run. But the third one isn’t there yet.

I am hoping that the question is when, not whether, he will earn that third cheer, by focusing on the issues as he promised he would and not saying anything that might be used by Donald Trump in the general election campaign.

The first cheer for Sanders is because at critical moments in his campaign he stuck to the issues the American people care about and refused to engage in personal attacks on Hillary Clinton, opposite from the vile anonymous Internet posters who call themselves “Bernie bros.”

One of the senator’s Iowa campaign leaders publicly repudiated these disgusting haters, cowards who hide behind anonymity. Sanders himself should be more explicit in denouncing them.

I will never forget the moment in the first debate, when Sanders was asked to address the issue of Clinton’s State emails, an obsession of the most partisan Republicans. He said, “I’m sick and tired of hearing about your damn emails.”

This statement was not only gracious, it was smart politics. It was followed by an ovation from the audience, from both his supporters and Clinton’s. According to most polls, almost eight out of ten Democrats agreed with Sanders then — and still do now.

Instead of personal attacks, for the most part, the Vermont Independent has focused on the two major issues that have become the themes of his White House campaign: the need to address the huge disparities in income and privileges between the super wealthy and most Americans, as well as to curb Wall Street firm abuses, and the need for major campaign finance reforms and the corrupting influence of big money in our political system.

And the fact is, there is very little substantive difference on these issues between Sanders and Clinton. Sanders’s narrow victory in Indiana on Tuesday night won’t significantly close the gap in Clinton’s huge lead in popular votes and delegates.

But it shows his message continues to resonate among many Democrats. The fact that he and Clinton share similar progressive positions and values portends well for party unity after the convention.

The second cheer that he deserves is due to his amazing ability to energize young people. Sanders has done what Barack Obama historically did in his 2008 campaign and, I hope, with the same positive impact on the November general elections.

In 2008, I experienced the pleasure/pain sensation of my son calling me and saying, “Dad, I love Hillary and Bill Clinton, but Barack Obama speaks to my generation and I am supporting him.”

Later, when I was asked by a reporter how I could explain my own son being for Obama despite my long years of friendship with Bill and Hillary Clinton, I answered: “I always told my son he should reach his own political opinions, independent of his father.

"I just didn’t think he would take me literally!”

Personal footnote: Today that same son is one of the most ardent Hillary supporters I know.

But Sanders hasn’t earned the third cheer yet because of his recent decision to attack Hillary Clinton personally.

Worse, his attacks are based on pure innuendo, not facts.

When asked to name a single issue where the former secretary of State was influenced in her position or vote because of big bank donations, he was unable to do so.

He also forgets to mention that Obama received similar donations and was similarly unaffected in his positions on the issues.

It is no coincidence that just about the time Sanders turned personally negative, he started to lose major primary states, such as New York, Ohio, Pennsylvania, Illinois, Missouri, Texas, and Florida.

The super-partisans in his campaign who urged him to go negative — urged on by the ratings obsessed media — have proven to be wrong.

Sen. Sanders: You are behind Hillary Clinton in the popular vote by over 3 million votes nationwide and more than 300 elected delegates. How can you ask superdelegates to vote for you in defiance of the will of the people?

If you were ahead of Clinton by 3 million votes, wouldn’t you be calling on superdelegates to support you for that very reason?

As for me, I predict Sanders will be a mensch and return to what he does best — supporting the progressive programs that have exemplified his candidacy from the beginning.

Sanders is entitled to campaign all the way through the convention and to fight for a progressive platform. That won’t hurt — it will help — the Democratic Party.

He should follow the path that Clinton pursued in her 2008 bid: She kept campaigning but did nothing to help the Republican candidate in November.

One thing Sanders and Clinton agree on 100 percent: Donald Trump is a dangerous demagogue who recklessly insults and lies about his opponents shamelessly and should never come close to being the president of the United States.

We Democrats have seen that for a long time.

We can’t say it any better than Ted Cruz did on Tuesday.

Lanny Davis is the principal in the Washington, D.C., law firm of Lanny J. Davis & Associates, which specializes in strategic crisis management. He served as President Clinton’s Special Counsel in 1996-98. Read more reports from Lanny Davis — Click Here Now.

Sanders will return to what he does best, supporting the progressive programs that have exemplified his candidacy from the beginning. Sanders is entitled to fight for a progressive platform. That will help the Democrats.